This grant seeks to develop novel immunotherapeutic approaches to the treatment of IDDM. The destruction of pancreatic islet cells in IDDM is initiated and/or mediated by T cells that recognize islet cell antigens and produce proinflammatory cytokines. The goal of this program is to develop immune-based reagents that specifically interfere with this pathogenetic process. To accomplish this goal, three projects are proposed, each of which utilizes the non-obese diabetic (NOD) mouse as an animal model of autoimmune disease, as well as autoantigen-specific human T cell clones to allow the development of specific forms of immunotherapy. Project I intends to study targeted delivery of genes that encode the regulatory cytokines IL-4, TGF-beta and IL-10 which are postulated to down regulate autoimmune disease. Initially, T cell clones transduced with these genes, in vitro, will be administered by adoptive transfer. If this approach is successful, the genes will then be incorporated into novel targeting vectors for delivery in situ. Project II proposes to block the proinflammatory cytokine cascade by two novel techniques. The first is adoptive transfer of T cells in which NFkappaB and IkappaB activity is blocked by dominant-negative gene transfer and, if successful, targeted gene delivery will be attempted in situ. In a second approach, T cell clones will be transduced with a construct that allows these cells to secrete anti-TNFalpha antibody at the site of inflammation. Project III will utilize a putative diabetogenic autoantigen (glutamic acid decarboxylase) to design altered peptide ligands (APLs) that either down- regulate autoantigen-specific Th-1 responses or induce naive CD4+ cells to become Th-2-like effectors. The therapeutic potential of candidate APLs will be tested in vivo in NOD/HLA DR4 transgenic mice and in vitro in a novel human dendritic cell-based system. Each of these three projects stands on its own but depends on the integration of multiple laboratories, an administrative core and an experimental animal core. In concert, these projects form a synergistic program directed toward the development of innovative approaches to the treatment of IDDM.